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Erosion dynamics and morphological evolution of composite volcanoes: Insights from analogue modelling

Roos Marina Johanna van Wees1, Engielle Paguican2, Daniel O'Hara1,3, Gabor Kereszturi4, Pablo Grosse5,6, Pierre Lahitte7, Matthieu Kervyn1

  • Affiliations: 1 Department of Geography, Vrije Universiteit Brussel, Brussels, Belgium; 2 Department of Geography, King\'s College London, London, UK; 3 GFZ German Research Centre for Geoscience, Potsdam, Germany; 4 Volcanic Risk Solutions, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand; 5 Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina; 6 Fundación Miguel Lillo, Tucumán, Argentina;   7 GEOPS, CNRS, Université Paris-Saclay, 91405 Orsay, France  

  • Presentation type: Talk

  • Presentation time: Tuesday 16:00 - 16:15, Room R280

  • Programme No: 3.5.10

  • Theme 3 > Session 5

Abstract

Volcanic landscapes, characterized by rapid growth and extended repose, serve as valuable natural laboratories for studying erosion patterns and rates across timescales. However, the complex morphologies resulting from concurrent erosional and depositional activities complicate the analysis of individual erosional processes in nature. Analogue models with rainfall-induced runoff provide a simplified, controlled setting to explore fluvial erosion, with well-constrained initial volcano cone size, slope, and complexity. This study uses analogue modelling to offer new insights into real-world volcanic landscape evolution. Experiments were conducted at the Vrije Universiteit Brussel volcanology laboratory using a custom-made rainfall-simulator. Cones made of a wet mixture of 70 µm silica powder were constructed on a drainage layer and the height, width and slopes were scaled from pristine natural composite volcanoes. The erosional and depositional evolution was documented at regular intervals using photogrammetry-derived DEM with sub-millimetre resolution. The influence of different initial flank slopes, the addition of a summit crater, erosion rate, and drainage basin forming were analyzed through geometric and drainage-based parameters. Results mimic erosion processes observed on natural volcanoes, where drainage basins widen and merge, decreasing drainage density over time. The presence of a crater accelerates initial summit erosion and drainage network maturity, creating wider basins. The steep upper slopes generate narrower gullies on the upper flanks, leading to a more rapid decrease in height. These various erosional processes, reflected in morphometric values, ultimately converge to a similar end state: equifinality represents a challenge for inferring the original shape of composite volcanoes from their degraded remnants.